Well, the price for the SD300 is roughly $360, depending on where you plan on buying it. I'm not sure about the Casio, however.
BUT, an alternative that I plan on getting is the SD200. It is 3.2MP as opposed to 4MP for the SD300. Other than that, I don't believe there is much technical difference between it and the SD300, except that it is $100 cheaper. The current best price I've seen is $241 shipped. Here are the reviews for the SD200 and SD300:
Both SD200/300 can take movies at 640x480 @ 30fps limited only by the size of the card, and they can take 320x240 @ 60fps for 1 minute.